This invention relates to optical elements such as lenses and the like. More particularly, it involves techniques for manufacturing such articles to provide them with preselected net reflectance characteristics.
Antireflective coatings have been used in the past on optical elements such as lenses and the like. It is generally desirable to keep the net reflectance of lenses as low as possible in order to increase the clarity of image formation. Conventional prior art techniques for making antireflection coatings include the repetitive deposition of various layers of materials having different indices of refraction on a surface of the article. The thicknesses of the individual layers must be carefully controlled and are generally about 1/4 of the wavelength of light in question. Typically, the thicknesses are in the order of about 1/4 micron.
It can be appreciated that the prior art methods of making antireflection coatings are extremely expensive, time consuming, and often difficult to consistently achieve. Additionally, the ideal materials for providing optimum results are not always readiliy available. Furthermore, such prior art antireflective coatings are relatively soft and, thus, are subject to damage by scratching during use thereby decreasing their useful lives even if the above noted problems are overcome during manufacture.
The present invention is directed to overcoming one or more of these problems.